JP2002305354A - Surface emission-type semiconductor laser element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface emission-type semiconductor laser element which is superior in light emission efficiency, has good temperature characteristic, has long life and emits the laser beam of a high wavelength area. SOLUTION: The surface emission-type semiconductor laser element 59 has an Al(Ga)As system first surface emission-type semiconductor laser structure part 52 which is formed on an n-GaAs substrate 51 and has 850 nm of oscillation wavelength, and a second surface emission-type semiconductor laser structure part 53 which is monolithically integrated on the first surface emission-type semiconductor laser structure part 52 and has an absorption area constituted of a GaInNAs material which is excited by the laser beam radiated from the first surface emission-type semiconductor laser structure part and has 1300 nm of oscillation wavelength. The second surface emission-type semiconductor laser structure part has a GaInNAs system quantum well active layer 70 and nondope DBR mirrors 66 and 74.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a long-wavelength surface emitting semiconductor laser device, and more particularly, to a long-wavelength surface emitting semiconductor laser having high luminous efficiency, good temperature characteristics and long life. It relates to an element.

[0002]

2. Description of the Related Art A surface-emitting type semiconductor laser device emits light in a direction orthogonal to a substrate. Unlike a conventional Fabry-Perot cavity type semiconductor laser device, a surface emitting type semiconductor laser device has two light emitting devices on the same substrate. Since a large number of surface emitting semiconductor laser elements can be arranged in a dimensional array, the semiconductor laser element has recently attracted attention in the field of data communication. The surface-emitting type semiconductor laser device is GaAs.
AlGaAs / Ga on semiconductor substrates such as s and InP
A pair of semiconductor multilayer film reflecting mirrors using As or the like is formed, and an active layer serving as a light emitting region is provided between the pair of reflecting mirrors. In addition, there has been proposed an oxide confined surface emitting semiconductor laser device having a current confinement structure formed of an Al oxide layer, which is excellent in current confinement effect and operates at a low threshold value and with high efficiency.

As a long-wavelength surface-emitting semiconductor laser device, a surface-emitting semiconductor laser device using a GaInNAs-based material for an active layer has attracted attention. Since a GaInNAs surface emitting semiconductor laser device can be formed on a GaAs substrate, Al (Ga) having good thermal conductivity and high reflectivity is used.
Since an As-based DBR mirror can be used, 1.2
Promising as a laser device capable of emitting light in a long wavelength range of μm to 1.6 μm.

Referring to FIG. 6, the configuration of a conventional GaInNAs-based long wavelength band surface emitting semiconductor laser device will be described.
FIG. 6 is a schematic sectional view showing the configuration of a conventional GaInNAs-based long wavelength band surface emitting semiconductor laser device. First, a conventional GaInNAs-based surface emitting semiconductor laser device 10 is:
On the n-GaAs substrate 12, the thickness of each layer is λ /
4n (λ is oscillation wavelength, n is refractive index) n-Al _0.9 Ga
The lower DBR mirror 14, the lower cladding layer 16, the quantum well active layer 18, the upper cladding layer 20, and the respective layers having a thickness of λ / 4 composed of 35 pairs of As / n-GaAs.
n (λ is oscillation wavelength, n is refractive index) p-Al _0.9 GaAs
It has a stacked structure of an upper DBR mirror 22 composed of 25 pairs of s / p-GaAs.

[0005] In the upper DBR mirror 22, one layer closer to the active layer 18 is made of p-Al _0.9 GaAs instead of p-Al _0.9 GaAs.
-Al of the AlAs layer 24 formed of the AlAs layer 24 and in a region other than the current injection region is selectively oxidized,
A current confinement layer composed of the oxide layer 25 is formed. Also,
The quantum well active layer 18 is made of GaInNAs / GaAs. The well layer is formed of Ga _0.63 In _0.37 N _0.01 As _0.99 having a well thickness of 8 nm and a compressive strain of 2.5%, and the barrier layer is formed of GaAs having a thickness of 10 nm. It is formed of layers.

In the laminated structure, the upper DBR mirror 22
Is formed below the AlAs layer 24 by photolithography and etching, for example, with a diameter of 30 μm.
It is processed into a circular mesa post of m. The laminated structure processed into the mesa post is oxidized at a temperature of about 400 ° C. in a steam atmosphere, and AlAs is applied from outside the mesa post.
By selectively oxidizing Al in the layer 24, a current confinement layer including the Al oxide layer 25 is formed. For example, if the width of the Al oxide layer 25 is a belt-like ring having a width of 10 μm, the area of the central AlAs layer 24, that is, the area (aperture) where current is injected, is about 80 μm ² (diameter 10 μm).
Becomes a circle.

The periphery of the mesa post is, for example, polyimide 2
6 embedded. A ring-shaped electrode is provided as a p-side electrode 28 in contact with the upper portion of the mesa post at a width of about 5 μm to 10 μm in outer circumference. The n-side electrode 30 is formed on the back surface of the n-GaAs substrate 12 after the back surface of the substrate is appropriately polished to adjust the substrate thickness to, for example, 200 μm. An electrode pad 32 for bonding to an external terminal with a wire is provided on the polyimide 26.
Are formed in a ring shape so as to be in contact with the ring electrode 28.

As described above, GaInNAs-based materials are:
Since it can be formed on a GaAs substrate, it is a useful material that can realize a long-wavelength surface-emitting semiconductor laser device using existing 850-nm band surface-emitting semiconductor laser device manufacturing technology.

[0009]

By the way, GaInN
The As-based material can have a longer wavelength by increasing the In composition (In content) in GaInNAs. However, increasing the In composition increases the amount of strain with respect to the GaAs substrate. The limit is about 30 to 40%, and the oscillation wavelength at that time is 1.1 to 1.25 μm
Rank. On the other hand, it is possible to increase the wavelength by increasing the N composition in GaInNAs. That is, in order to make the wavelength longer than 1.2 μm, it is necessary to control the wavelength by adjusting the N composition. Usually, when the composition of N is in the range of 0.5% to 1%, a surface-emitting type semiconductor laser device having an emission wavelength of 1.3 μm can be realized.

However, when the N composition is increased, the peak intensity of photoluminescence (PL) decreases. For example, N
Even in the case of the composition of 0.5%, compared with the case not containing N,
The PL intensity is reduced to about 1/100. This is considered to be because the crystallinity is deteriorated by introducing N. In order to realize a surface emitting semiconductor laser device having an emission wavelength of 1.55 μm, it is necessary to increase the composition of N to about 5%, but in this case, the crystallinity is further deteriorated, and The PL peak intensity decreases. In other words, although the GaInNAs-based material is an excellent material capable of realizing a long-wavelength band surface emitting semiconductor laser device on a GaAs substrate, it is necessary to realize a long-wavelength surface emitting semiconductor laser device of 1.3 μm or more. , 0.5% or more. However, in this case, the crystallinity is deteriorated, the PL peak intensity is reduced, and the reliability of the device is affected. When the emission wavelength is increased to about 1.55 μm, the N composition needs to be increased to about 5%, so that the influence is particularly large.

There is also a problem that the quantum efficiency is reduced due to the deterioration of crystallinity due to the introduction of N. For example, in a surface emitting semiconductor laser device using an Al _0.9 GaAs / GaAs DBR mirror, an Al _0.9 GaAs
Since a heterospike exists at the interface between the layer and the GaAs layer, a certain amount of impurities, for example, about 1 to 5 × 10 ¹⁸ cm ⁻³ , is doped in order to prevent an increase in operating voltage due to the heterospike. Since the free carriers are absorbed by the impurities, the quantum efficiency is reduced, and the light output is greatly reduced.

As described above, since a GaInNAs surface emitting semiconductor laser device can be formed on a GaAs substrate, Al (Ga) A having good thermal conductivity and high reflectivity can be obtained.
Since an s-system DBR mirror can be used, 1.2 μm
Although attention has been paid to a surface-emitting type semiconductor laser device capable of emitting light in a long wavelength range of m to 1.6 μm, the conventional configuration has high efficiency, good temperature characteristics, and high reliability. It has been difficult to realize a band-emission semiconductor laser device. Therefore, there is a demand for a surface-emitting semiconductor laser device having higher efficiency, better temperature characteristics, and a longer life than conventional GaInNAs-based surface-emitting semiconductor laser devices.

By the way, another method has been proposed as a method for realizing a surface emitting semiconductor laser device in a long wavelength band. For example, Japanese Patent Publication No. Hei 10-501927 discloses a short wavelength VCSEL (Vertical Cavity Surface-Emitting Sem).
discloses a long wavelength optical device having a long wavelength VCSEL optically pumped by a short wavelength VCSEL. The configuration of the disclosed long wavelength band optical device will be described with reference to FIG. Optical device 4
0 is a short-wavelength VCSEL 41 of 980 nm pumped by electric energy, as shown in FIG.
98 pumped by the light oscillated by the CSEL 41
A long wavelength VCSEL 42 having a wavelength longer than 0 nm. The long wavelength VCSEL 42 is provided on a GaAs substrate 43,
It has an undoped lower GaAs / AlAs mirror 44, a light emitting structure 45, and an upper dielectric mirror 46, and the GaAs substrate 43 of the long wavelength VCSEL 42 is shorted by an optical adhesive 47 or a metal bond or by a wafer bonding technique. The wavelength VCSEL 41 is bonded to the GaAs substrate 48. Short wavelength VCSEL 41 is also long wavelength VCSE
It has the same structure as L42.

However, the above-described optical device 40 requires a wafer bonding technique or the like to optically integrate the long-wavelength VCSEL 42 and the short-wavelength VCSEL 41, and thus has a problem of extremely low productivity. However, it is not suitable for mass production of a long wavelength surface emitting semiconductor laser device that solves the above-mentioned problems.

It is an object of the present invention to provide a GaInNA having high luminous efficiency, good temperature characteristics, and a long life.
An object of the present invention is to provide an s-based surface emitting semiconductor laser device.

[0016]

SUMMARY OF THE INVENTION The present inventor has proposed a high-efficiency,
In order to realize a long-wavelength surface-emitting type semiconductor laser device with good temperature characteristics and long life, it is necessary to use a GaInNAs-based material for the absorption region and eliminate the need for a wafer bonding technology because of the various problems described above. With the idea of an optical device consisting of a two-stage VCSEL integrated in the above, the present invention was invented after experiments. That is, it is Ga
An Al (Ga) As-based mirror formed on an As substrate and
a first surface emitting semiconductor laser structure having an aAs / AlGaAs quantum well active layer, pumped by electric energy, and emitting light having an oscillation wavelength of 850 nm;
A second surface emitting semiconductor laser device having an NAs quantum well active layer and an undoped Al (Ga) As-based mirror, optically coupled to the first surface emitting semiconductor laser structure, and oscillating at an oscillation wavelength of 1300 nm; Is a monolithically integrated optical device.

In order to achieve the above object, a surface-emitting type semiconductor laser device according to the present invention comprises a first surface-emitting type semiconductor laser structure formed on a GaAs substrate and a first surface-emitting type semiconductor laser. Monolithically integrated on the structure,
A first surface-emitting type semiconductor laser structure having a GaInNAs-based second surface-emitting type semiconductor laser structure having an absorption region made of a GaInNAs-based material having a bandgap wavelength longer than the oscillation wavelength of the first surface-emitting type semiconductor laser; The second surface-emitting type semiconductor laser structure is optically excited by the laser light emitted from the semiconductor laser structure, and the laser light of the second surface-emitting type semiconductor laser is output.

In the present invention, the absorption region is a compound semiconductor layer that absorbs laser light oscillated by the first surface emitting semiconductor laser structure. The active layer may have a bulk, a single quantum well structure, or a multiple quantum well structure. In the case of a quantum well structure, light confinement layers may be provided on both sides thereof. The active layer of the second surface emitting semiconductor laser structure is formed of a GaInNAs-based active layer.
Since no current is directly passed through the aInNAs active layer, the DBR
Internal heat generated by a mirror or the like is suppressed. Therefore, the temperature rise of the active layer can be suppressed small. That is, by eliminating the presence of the current and heat, generation and growth of crystal defects such as dislocations are suppressed, and as a result, the life is prolonged. Also, since the quantum well active layer of the second surface emitting semiconductor laser structure is formed of GaInNAs,
Good temperature characteristics. Further, since the second surface-emitting type semiconductor laser structure is made of GaInNAs, the epitaxial growth can be continuously performed on the GaAs substrate following the first surface-emitting type semiconductor laser structure. That is,
Since the second surface-emitting type semiconductor laser structure is monolithically integrated on the first surface-emitting type semiconductor laser structure, the productivity is remarkably higher than when a conventional bonding method or the like is used.

In a preferred embodiment of the present invention, the absorption area of the second surface-emitting type semiconductor laser structure is Ga _1-x In _x N
_y As _1-y (0 ≦ X ≦ 0.45, 0 ≦ y ≦ 0.1) or Ga _1-x In _x N _y Sb _z As _1-yz (0 ≦ X ≦
0.45, 0 ≦ y ≦ 0.1, 0 ≦ z ≦ 0.05). When X exceeds 0.45, the amount of strain increases, and it becomes difficult to form a good crystal. When y exceeds 0.1, PL emission intensity remarkably decreases due to an increase in crystal defects. When z exceeds 0.05, the effect as a surfactant is lost. When the absorption region contains Sb,
Since Sb acts as a surfactant during crystal growth, there is an effect that three-dimensional growth is suppressed and a good crystal is obtained.

In a further preferred embodiment of the present invention, the DBR mirror on at least one side of the absorption region of the second surface-emitting type semiconductor laser structure is a DBR mirror made of an undoped semiconductor multilayer film. Since no current flows directly through the second surface-emitting type semiconductor laser structure, the DBR mirror does not need to have a reduced resistance and can be undoped. Thereby, free carrier absorption by impurities in the DBR mirror can be suppressed, and as a result, luminous efficiency is improved.

[0021]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, the film type, film thickness,
The film forming method, other dimensions, and the like are examples for facilitating the understanding of the present invention, and the present invention is not limited to these examples. Embodiment Example This embodiment is an example of an embodiment of a surface-emitting type semiconductor laser device according to the present invention, and FIG. 1 is a schematic cross-section showing a configuration of the surface-emitting type semiconductor laser device of this embodiment. FIG. The surface-emitting type semiconductor laser device 50 of this embodiment is
Oscillation wavelength 850n formed on n-GaAs substrate 51
m GaAs / AlGaAs-based first surface-emitting type semiconductor laser structure 52 and monolithically integrated on the first surface-emitting type semiconductor laser structure 52 and emitted from the first surface-emitting type semiconductor laser structure. And a GaInNAs-based second surface-emitting type semiconductor laser structure 53 having an oscillation wavelength of 1300 nm which is optically excited by a laser beam.

First surface-emitting type semiconductor laser structure 52
Means that the thickness of each layer on the n-GaAs substrate 51 is
λ / 4n (λ is the oscillation wavelength, n is the refractive index of the constituent layer,
E) n-Al_0.9GaAs / n-Al₀._TwoGaAs
Lower DBR mirror 54 composed of 35 pairs, lower clad
Layer 56, quantum well active layer 58, upper cladding layer 60,
And the thickness of each layer is λ / 4n (λ is the oscillation wavelength, n
Is the refractive index) p-Al_{0. 9}GaAs / p-Al₀._TwoGa
Stack structure of upper DBR mirror 62 composed of 25 pairs of As
It has a structure.

Lower DBR mirror 54 and upper DBR mirror
-62 functions as a reflector for light in the 850 nm wavelength band.
The active layer 58 has an oscillation wavelength of 850 nm.
m GaAs / Al_0.2Formed as GaAs quantum well
Have been. Further, in the upper DBR mirror 62, the active layer 5
8 is n-Al_{0. 9}Instead of GaAs layer
Formed by the AlAs layer 64 and other than the current injection region
Is selectively oxidized in the AlAs layer 64 in the region of
A current confinement layer composed of the l-oxide layer 65 is formed. Ma
The upper DBR mirror 62 of the stacked structure
Leaving a part of the lower layer below the activation layer 65, for example,
Etch the first mesa post in the form of a 0 μm circular air post
Has been processed. The current injection region is, for example, Al
When the width of the oxide layer 65 is a belt-like ring having a width of 15 μm,
The area of the central AlAs layer 64, that is, the area into which current is injected.
(Aperture) is about 80 μm^Two(Diameter of 10μm)
It takes shape.

Second surface-emitting type semiconductor laser structure 53
Is the upper DB of the first surface-emitting type semiconductor laser structure 52
On the R mirror 62, the thickness of each layer is λ / 4n.
Doped Al_0.9GaAs / Al_0.230 pairs of GaAs
Second lower DBR mirror 66 composed of a
68, a GaInNAs-based quantum well active layer 70,
Head layer 72 and a node having a thickness of λ / 4n
Doped Al_0.9GaAs / Al_0.225 pairs of GaAs
Laminated structure composed of a second upper DBR mirror 74 composed of
It has. GaInNAs-based quantum well active layer 70
Is composed of GaInNAs / GaAs, and the well layer is
Ga with 2 units and a compressive strain of 2.5% with a thickness of 8 nm_0.63I
n_0.37N _0.01As_0.99And the GaAs barrier layer is a film
It is formed of a GaAs layer having a thickness of 10 nm and has a thickness of 1.3 μm.
It oscillates at an oscillation wavelength of m. Also, the second lower and upper DB
The R mirrors 66 and 74 reflect light in the 1300 nm wavelength band.
It has a thickness that functions as a mirror.

The laminated structure including the second lower DBR mirror 66, the lower cladding layer 68, the GaInNAs-based quantum well active layer 70, the upper cladding layer 72, and the second upper DBR mirror 74 has a smaller diameter than the first mesa post, for example. The second mesa post in the form of a circular air post having a diameter of 30 μm is etched. On the outer periphery of the upper surface of the first mesa post, a p-side electrode 76 made of a ring-shaped metal film having a width of about 5 μm to 10 μm is provided. An SiN _x protective film 78 is formed outside the laminated structure except for the p-side electrode 76. The n-GaAs substrate 51 is polished to a thickness of, for example, 200 μm, and an n-side electrode 80
Are formed.

The surface-emitting type semiconductor laser device 50 of this embodiment uses GaIn laser light emitted from the first surface-emitting type semiconductor laser structure 52 at a wavelength of 850 nm.
The second surface-emitting type semiconductor laser structure 53 having the 1.3 μm wavelength active layer 70 made of a NAs quantum well can be optically excited to emit 1.3 μm wavelength laser light. In the surface-emitting type semiconductor laser device 50, GaInNA
Since no current is directly injected into the s quantum well active layer 70, the device life is determined by the first surface emitting semiconductor laser structure 52. Therefore, the life of the device is longer than that of the conventional GaInNAs surface emitting semiconductor laser device. Also, Ga
Since current is not directly injected into the InNAs quantum well active layer, the 1.3 μm wavelength DBR mirrors 66 and 74 formed on both sides of the GaInNAs quantum well active layer 70 can be non-doped. Therefore, since the free carrier absorption due to the impurities can be reduced, an improvement in the optical output (efficiency) can be expected.

Hereinafter, a method for fabricating the surface emitting semiconductor laser device of this embodiment will be described with reference to FIGS. FIGS. 2 (a) and (b) and FIGS. 3 (c) and (d)
FIGS. 4A to 4C are cross-sectional views for respective steps in manufacturing the surface-emitting type semiconductor laser device of the embodiment. First, FIG.
As shown in FIG.
N-Al _0.9 GaAs / n-
Al _0.2 lower DBR mirror 54 of GaAs of 35 pairs, the lower cladding layer 56, a quantum well active layer 58, upper cladding layer _{60, p-Al 0.9 GaAs /} p-Al 0.2 G
An upper DBR mirror 62 composed of 25 pairs of aAs is formed to form a first stacked structure. Where the upper DBR
When the mirror 62 is formed, an AlAs layer 64 is formed instead of the AlGaAs layer on the side closer to the active layer in order to form an Al oxide layer which will be a current confinement layer in a later step.

Further, as shown in FIG.
According to the D method, a second lower DBR mirror 66 composed of 30 pairs of non-doped Al _0.9 GaAs / Al _0.2 GaAs, a lower cladding layer 68, a GaInNAs-based quantum well active layer 70 are successively formed on the upper DBR mirror 62 in succession. Upper cladding layer 72 and undoped Al _0.9 GaAs
Second upper DB consisting of 25 pairs of s / Al _0.2 GaAs
An R mirror 74 is formed to produce a second laminated structure.

Next, as shown in FIG. 3 (c), the first layered structure of the first stacked structure leaving the lower layer portion of the first upper DBR mirror is removed by a normal photolithography process, followed by a dry etching technique or a chemical etching technique. 1 upper DBR
The mirror 62 and the second stacked structure are etched to form, for example, a circular first mesa post having a diameter of 40 μm.
Next, as shown in FIG. 3D, the second laminated structure is etched again by a normal photolithography process and then by a dry etching technique or a chemical etching technique to form a circular second mesa post having a diameter of, for example, 30 μm. Form.

Next, an oxidation treatment is performed in a steam atmosphere at a temperature of about 400 ° C. to selectively oxidize the AlAs layer 64 from outside the mesa post, thereby converting the AlAs layer 64 to an Al oxide layer 65. At the time of Al oxidation, for example, when the width of the Al oxide layer is 15
In the case of a belt-like ring shape of μm, the oxidation time is controlled so that the area of the center AlAs layer 64, that is, the area (aperture) where current is injected is a circle of about 80 μm ² (diameter of 10 μm).

Next, a SiN _x protective film 78 is formed on the entire surface of the laminated structure except for the ring-shaped p-side electrode 76, and then a ring-shaped contact is formed on the upper part of the first mesa post with a width of about 5 μm in outer circumference. Is formed. Also, n-Ga
The back surface of the As substrate 51 is polished to reduce the substrate thickness to, for example, 200
After adjusting to a thickness of μm, an n-side electrode 80 is formed on the back surface.

Through the above steps, a first surface-emitting type semiconductor laser structure 52 having an oscillation wavelength of 850 nm and a monolithic integration on the first surface-emitting type semiconductor laser structure 52,
A surface-emitting type semiconductor laser device having a second surface-emitting type semiconductor laser structure 53 having an oscillation wavelength of 130 nm, which is optically excited by laser light emitted from the first surface-emitting type semiconductor laser structure, and emitting 1300 nm laser light. 50 can be produced.

EXPERIMENTAL EXAMPLE 1 A sample having the same structure as the surface emitting semiconductor laser device 50 of this embodiment was prepared according to the above-described method, and was subjected to an ACC (Auto Current Control) at a temperature of 85 ° C. and an injection current of 10 mA.
ol) performs drive motion to obtain the results shown in FIG. FIG. 4 is a graph showing the change rate of the optical output of the surface-emitting type semiconductor laser device corresponding to the elapse of the operation time. Graph (1) shows the result of the sample of the surface-emitting type semiconductor laser device 50 of the present embodiment. The graph (2) shows the result of the conventional GaInNAs-based surface emitting semiconductor laser device 10 described above. As can be seen from FIG. 4, the conventional surface-emitting type semiconductor laser device 10
While the light output of the surface emitting semiconductor laser device 50 sharply decreases with the elapse of the operation time,
Even after an operation time of 0000 hours or more, there is almost no change in the light output, and the reliability is remarkably improved.

Experimental Example 2 FIG. 5 shows the injection current versus light output characteristics of the sample of the surface emitting semiconductor laser device 50 and the conventional surface emitting semiconductor laser device 10. The measurement was performed by a continuous (CW) operation at 25 ° C. In the figure, a graph (1) shows the result of 50 samples of the surface-emitting type semiconductor laser device of the present embodiment, and a graph (2) shows the result of the above-mentioned conventional surface-emitting type semiconductor laser device 10. As can be seen from FIG. 5, the light output of the sample of the surface-emitting type semiconductor laser device 50 is significantly higher than that of the conventional surface-emitting type semiconductor laser device 10, and the luminous efficiency is greatly improved.

Further, as a result of measuring the temperature characteristics of the injection current versus the optical main characteristic, the light output at a temperature of 20 ° C. and the temperature of 85 ° C.
Comparing the optical outputs at the time of the above, while the optical output of the conventional surface-emitting type semiconductor laser device 10 is reduced to about 1/10, the decrease of the optical output of the sample of the surface-emitting type semiconductor laser device 50 is as follows. It was remarkably small, about 2/3. Experimental examples 1 and 2
According to the results, the surface-emitting type semiconductor laser device 50 of the present embodiment has improved reliability, high luminous efficiency, and good temperature characteristics.

In this embodiment, the second surface-emitting type semiconductor
The active layer 70 of the laser structure 53 is made of Ga_0.63In_0.37N
_0.01As_0.99/ GaAs quantum well structure
But instead of Ga_1-XIn_XN_ySb_zAs
_1-yz(0 ≦ X ≦ 0.45, 0 ≦ y ≦ 0.1, 0 ≦ z ≦
0.05) / GaAs quantum well structure, for example, Ga_0.63I
n_{0. 37}N_0.01Sb_0.016As_0.974/ GaAs quantum well
It can also be configured as a structure. Thereby, the well layer
It has the effect of improving the quality. The material of the barrier layer is G
It is not necessary to limit to aAs.

In this embodiment, an example in which a surface-emitting semiconductor laser structure in the 850 nm band is used as the first surface-emitting semiconductor laser structure for the excitation light source, but the present invention is not limited to the 850 nm band. And the band gap wavelength of the laser structure on the side where the band gap wavelength is excited is shorter than the band gap wavelength of the laser structure on the side where the excitation is performed. For example, the band gap wavelength of the laser structure on the side where the excitation is performed is 1.2 μm. In the case of の 1.65 μm, the band gap wavelength of the excitation light source can be selected in the range of 0.6 μm to 1.25 μm.

[0038]

According to the present invention, the first laser structure formed on the GaAs substrate and the monolithically integrated laser structure on the first laser structure are arranged so that the oscillation wavelength of the first laser structure is higher than that of the first laser structure. A surface-emitting type semiconductor laser device is constituted by a second laser structure having an absorption region made of a GaInNAs-based material having a long band gap wavelength, and a second laser structure is formed by laser light emitted from the first laser structure. A long-life surface-emitting type semiconductor laser device that exhibits stable temperature characteristics by emitting light from a portion and emits laser light in a long wavelength range with high luminous efficiency is realized.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating a configuration of a surface emitting semiconductor laser device according to an embodiment.

FIGS. 2A and 2B are cross-sectional views for respective steps when fabricating the surface-emitting type semiconductor laser device of the embodiment.

FIGS. 3 (c) and (d) are FIGS.
FIG. 5B is a cross-sectional view illustrating a step of manufacturing the surface-emitting type semiconductor laser device according to the embodiment, following FIG.

FIG. 4 is a graph showing a change rate of an optical output of a surface-emitting type semiconductor laser device corresponding to an elapse of an operation time.

FIG. 5 is a graph showing a relationship between an injection current and a light output.

FIG. 6 is a schematic cross-sectional view showing a configuration of a conventional long wavelength band GaInNAs-based surface emitting semiconductor laser device.

FIG. 7 is a cross-sectional view illustrating a configuration of an optical device.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 Conventional GaInNAs-based surface emitting semiconductor laser device 12 n-GaAs substrate 14 lower DBR mirror composed of 35 pairs of n-Al _0.9 GaAs / n-GaAs 16 lower cladding layer 18 quantum well active layer 20 upper cladding layer 22 p− Al _0.9 GaAs / made of p-GaAs of 25 pairs the upper DBR mirror 24 AlAs layer 25 Al oxide layer 26 of polyimide 28 p-side electrode 30 n-side electrode 32 electrode pad 40 optical device 41 a short wavelength VCSEL 42 long wavelength VCSEL 43 GaAs substrate 44 Lower GaAs / AlAs mirror 45 Light emitting structure 46 Upper dielectric mirror 47 Optical adhesive 48 GaAs substrate 50 Surface emitting semiconductor laser device 51 of the embodiment 51 n-GaAs substrate 52 First surface emitting semiconductor laser with oscillation wavelength of 850 nm Structure 5 Second surface emitting semiconductor laser structure portion _{54 n-Al 0.9 GaAs / n} -Al 0 the oscillation wavelength 1300 nm. ₂ lower formed of GaAs of 35 pairs DBR mirror 56 lower cladding layer 58 quantum well active layer 60 upper cladding layer 62 _{p-Al 0.9 GaAs / p-} Al 0. 2 GaAs of the second lower DBR mirror 68 lower cladding consisting of an upper DBR mirror 64 AlAs layer 65 Al oxide layer 66 non-doped Al _0.9 GaAs / Al _0.2 GaAs of 30 pairs consisting of 25 pairs Layer 70 GaInNAs-based quantum well active layer 72 Upper cladding layer 74 Second upper DBR mirror consisting of 25 pairs of non-doped Al _0.9 GaAs / Al _0.2 GaAs 76 P-side electrode 78 SiNx protective film 80 N-side electrode

Claims (5)

[Claims] 1. A first surface-emitting type semiconductor laser structure formed on a GaAs substrate, and a first surface-emitting type semiconductor laser structure monolithically integrated on the first surface-emitting type semiconductor laser structure. A second surface-emitting type semiconductor laser structure having a GaInNAs-based material having an absorption region having a band gap wavelength longer than the oscillation wavelength of the portion, and emitting light from the first surface-emitting type semiconductor laser structure. A surface-emitting type semiconductor laser device characterized in that a second surface-emitting type semiconductor laser structure is optically excited by a laser beam to output laser light of the second surface-emitting type semiconductor laser. 2. The absorption region of the second surface-emitting type semiconductor laser structure portion has at least Ga _{1 -x} In _x N _y As _{1 -y} (0 ≦ X
2. The surface emitting semiconductor laser device according to claim 1, wherein the surface emitting semiconductor laser device is a quantum well or a bulk composed of (≦ 0.45, 0 ≦ y ≦ 0.1). 3. The absorption area of the second surface-emitting type semiconductor laser structure part is at least Ga ₁ -x In _x N _y Sb _z As.
_1-yz (0 ≦ X ≦ 0.45, 0 ≦ y ≦ 0.1, 0 ≦ z ≦
2. The surface emitting semiconductor laser device according to claim 1, wherein the surface emitting semiconductor laser device is a quantum well layer or a bulk layer made of 0.05). 4. The DBR mirror according to claim 1, wherein the DBR mirror on at least one side of the absorption region of the second surface-emitting type semiconductor laser structure is a DBR mirror made of an undoped semiconductor multilayer film. 2. The surface emitting semiconductor laser device according to claim 1. 5. The oscillation wavelength of the first surface-emitting type semiconductor laser structure is in the range of 0.6 μm to 1.25 μm, and the oscillation wavelength of the second surface-emitting type semiconductor laser structure is 1.2 μm or more. 5. The surface-emitting type semiconductor laser device according to claim 1, wherein the surface-emitting type semiconductor laser device is in a range of 1.65 [mu] m or less.